'\" te
.\" Copyright (c) 2007, Sun Microsystems Inc. All Rights Reserved.
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
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.TH U8_STRCMP 9F "February 21, 2023"
.SH NAME
u8_strcmp \- UTF-8 string comparison function
.SH SYNOPSIS
.nf
#include <sys/sunddi.h>

\fBint\fR \fBu8_strcmp\fR(\fBconst char *\fR\fIs1\fR, \fBconst char *\fR\fIs2\fR, \fBsize_t\fR \fIn\fR,
     \fBint\fR \fIflag\fR, \fBsize_t\fR \fIunicode_version\fR, \fBint *\fR\fIerrno\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI)
.SH PARAMETERS
.ne 2
.na
\fB\fIs1\fR, \fIs2\fR\fR
.ad
.RS 20n
Pointers to null-terminated UTF-8 strings
.RE

.sp
.ne 2
.na
\fB\fIn\fR\fR
.ad
.RS 20n
The maximum number of bytes to be compared.  If 0, the comparison is performed
until either or both of the strings are examined to the string terminating null
byte.
.RE

.sp
.ne 2
.na
\fB\fIflag\fR\fR
.ad
.RS 20n
The possible comparison options constructed by a bit-wise-inclusive-OR of the
following values:
.sp
.ne 2
.na
\fB\fBU8_STRCMP_CS\fR\fR
.ad
.sp .6
.RS 4n
Perform case-sensitive string comparison. This is the default.
.RE

.sp
.ne 2
.na
\fB\fBU8_STRCMP_CI_UPPER\fR\fR
.ad
.sp .6
.RS 4n
Perform case-insensitive string comparison based on Unicode upper case
converted results of \fIs1\fR and \fIs2\fR.
.RE

.sp
.ne 2
.na
\fB\fBU8_STRCMP_CI_LOWER\fR\fR
.ad
.sp .6
.RS 4n
Perform case-insensitive string comparison based on Unicode lower case
converted results of \fIs1\fR and \fIs2\fR.
.RE

.sp
.ne 2
.na
\fB\fBU8_STRCMP_NFD\fR\fR
.ad
.sp .6
.RS 4n
Perform string comparison after \fIs1\fR and \fIs2\fR have been normalized by
using Unicode Normalization Form D.
.RE

.sp
.ne 2
.na
\fB\fBU8_STRCMP_NFC\fR\fR
.ad
.sp .6
.RS 4n
Perform string comparison after \fIs1\fR and \fIs2\fR have been normalized by
using Unicode Normalization Form C.
.RE

.sp
.ne 2
.na
\fB\fBU8_STRCMP_NFKD\fR\fR
.ad
.sp .6
.RS 4n
Perform string comparison after \fIs1\fR and \fIs2\fR have been normalized by
using Unicode Normalization Form KD.
.RE

.sp
.ne 2
.na
\fB\fBU8_STRCMP_NFKC\fR\fR
.ad
.sp .6
.RS 4n
Perform string comparison after \fIs1\fR and \fIs2\fR have been normalized by
using Unicode Normalization Form KC.
.RE

Only one case-sensitive or case-insensitive option is allowed. Only one Unicode
Normalization option is allowed.
.RE

.sp
.ne 2
.na
\fB\fIunicode_version\fR\fR
.ad
.RS 20n
The version of Unicode data that should be used during comparison. The
following values are supported:
.sp
.ne 2
.na
\fB\fBU8_UNICODE_320\fR\fR
.ad
.sp .6
.RS 4n
Use Unicode 3.2.0 data during comparison.
.RE

.sp
.ne 2
.na
\fB\fBU8_UNICODE_500\fR\fR
.ad
.sp .6
.RS 4n
Use Unicode 5.0.0 data during comparison.
.RE

.sp
.ne 2
.na
\fB\fBU8_UNICODE_LATEST\fR\fR
.ad
.sp .6
.RS 4n
Use the latest Unicode version data available, which is Unicode 5.0.0.
.RE

.RE

.sp
.ne 2
.na
\fB\fIerrno\fR\fR
.ad
.RS 20n
A non-zero value indicates that an error has occurred during comparison. The
following values are supported:
.sp
.ne 2
.na
\fB\fBEBADF\fR\fR
.ad
.RS 10n
The specified option values are conflicting and cannot be supported.
.RE

.sp
.ne 2
.na
\fB\fBEILSEQ\fR\fR
.ad
.RS 10n
There was an illegal character at \fIs1\fR, \fIs2\fR, or both.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
There was an incomplete character at \fIs1\fR, \fIs2\fR, or both.
.RE

.sp
.ne 2
.na
\fB\fBERANGE\fR\fR
.ad
.RS 10n
The specified Unicode version value is not supported.
.RE

.RE

.SH DESCRIPTION
After proper pre-processing, the \fBu8_strcmp()\fR function compares two UTF-8
strings byte-by-byte, according to the machine ordering defined by the
corresponding version of the Unicode Standard.
.sp
.LP
When multiple comparison options are specified, Unicode Normalization is
performed after case-sensitive or case-insensitive processing is performed.
.SH RETURN VALUES
The \fBu8_strcmp()\fR function returns an integer greater than, equal to, or
less than 0 if the string pointed to by \fIs1\fR is greater than, equal to, or
less than the string pointed to by \fIs2\fR, respectively.
.sp
.LP
When \fBu8_strcmp()\fR detects an illegal or incomplete character, such
character causes the function to set \fIerrno\fR to indicate the error.
Afterward, the comparison is still performed on the resultant strings and a
value based on byte-by-byte comparison is always returned.
.SH CONTEXT
The \fBu8_strcmp()\fR function can be called from user or interrupt context.
.SH EXAMPLES
\fBExample 1 \fRPerform simple default string comparison.
.sp
.in +2
.nf
#include <sys/sunddi.h>

int
docmp_default(const char *u1, const char *u2) {
    int result;
    int ;

    result = u8_strcmp(u1, u2, 0, 0, U8_UNICODE_LATEST, &errno);
    if (errno == EILSEQ)
        return (-1);
    if (errno == EINVAL)
        return (-2);
    if (errno == EBADF)
        return (-3);
    if (errno == ERANGE)
        return (-4);
.fi
.in -2

.LP
\fBExample 2 \fRPerform upper case based case-insensitive comparison with
Unicode 3.2.0 date.
.sp
.in +2
.nf
#include <sys/sunddi.h>

int
docmp_caseinsensitive_u320(const char *u1, const char *u2) {
    int result;
    int errno;

    result = u8_strcmp(u1, u2, 0, U8_STRCMP_CI_UPPER,
        U8_UNICODE_320, &errno);
    if (errno == EILSEQ)
        return (-1);
    if (errno == EINVAL)
        return (-2);
    if (errno == EBADF)
        return (-3);
    if (errno == ERANGE)
        return (-4);

    return (result);
}
.fi
.in -2

.LP
\fBExample 3 \fRPerform Unicode Normalization Form D.
.sp
.LP
Perform Unicode Normalization Form D and uppercase-based case-insensitive
comparison with Unicode 3.2.0 date.

.sp
.in +2
.nf
#include <sys/sunddi.h>

int
docmp_nfd_caseinsensitive_u320(const char *u1, const char *u2) {
    int result;
    int errno;

    result = u8_strcmp(u1, u2, 0,
        (U8_STRCMP_NFD|U8_STRCMP_CI_UPPER), U8_UNICODE_320,
        &errno);
    if (errno == EILSEQ)
        return (-1);
    if (errno == EINVAL)
        return (-2);
    if (errno == EBADF)
        return (-3);
    if (errno == ERANGE)
        return (-4);

    return (result);
}
.fi
.in -2

.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
.TE

.SH SEE ALSO
.BR u8_textprep_str (3C),
.BR u8_validate (3C),
.BR attributes (7),
.BR u8_textprep_str (9F),
.BR u8_validate (9F),
.BR uconv_u16tou32 (9F)
.sp
.LP
The Unicode Standard (http://www.unicode.org)
